乌兰布和沙漠东北缘生态承载力时空动态分析

Spatial-temporal dynamics of ecological carrying capacity of the northeastern margin of the Ulan Buh Desert

生态承载力是衡量生态系统稳定性的重要指标之一,其时空变化分析有助于了解地区生态环境变化趋势,对生态环境的治理与恢复评价、环境整体的可持续发展研究以及国土资源优化也具有全面的参考价值。以乌兰布和沙漠东北缘的干旱半干旱地区为研究区,以Landsat系列遥感数据为数据源,基于地区的实际生态状况,构建生态承载力综合指标评价体系,进而获得地区生态承载力时空分布及演变格局,并从降雨、温度以及土地利用变化的角度对生态承载力的变化进行驱动分析。结果表明,1990—2020年乌兰布和沙漠东北缘区域的生态承载力整体呈现先减少后增加的趋势,其中黄河以北的灌区向西南方向的荒漠化区域不断扩张,较高生态承载力的面积占比大幅度增加,高生态承载力面积降低,受土地开发利用的影响较大,其次是温度和降雨,而黄河以南的荒漠化区域以中生态承载力为主,在2010年之前大面积转为较低生态承载力,到2020年又恢复到中生态承载力,受温度影响较大,其次是降雨和灌草植被覆盖状况的变化。

Ecological carrying capacity is an important indicator used to measure the stability of an ecosystem.The spatial-temporal change analysis of the ecological carrying capacity can help understand the changing trend of a regional ecological environment and serve as a comprehensive reference for the evaluation of ecological management and restoration,research on the overall sustainable development of an environment,and the optimization of land resources.Targeting the arid and semi-arid regions at the northeastern margin of the Ulan Buh Desert,this study constructed a comprehensive index evaluation system of ecological carrying capacity based on the actual ecological conditions of the regions and Landsat remote sensing images as the data source.Then,this study determined the spatial-temporal distribution and evolution pattern of regional ecological carrying capacity and made a driver analysis of the change in the ecological carrying capacity from the angles of rainfall,temperature,and land use changes.The results show that the ecological carrying capacity of the northeastern margin of the Ulan Buh Desert showed a first decreasing and then increasing trend from 1990 to 2020.The irrigated areas north of the Yellow River continued to expand to the desertification areas in the southwest.As a result,the percentage of the area with relatively high ecological carrying capacity increased greatly,while the area with high ecological carrying capacity decreased.The change in the ecological carrying capacity of the irrigated areas was mainly affected by land development and utilization,followed by temperature and rainfall.In contrast,the ecological carrying capacity of the desertification areas south of the Yellow River was mainly at a moderate level,which was shifted to a low level in large areas before 2010 and was restored to a moderate level in 2020.The change in the ecological carrying capacity of the desertification areas was greatly affected by temperature,followed by rainfall and changes in shrub and grass vegetation cover.